Tumor growth in in vivo treatment study with 64Cu-ATSM. (A) Tumor growth curve. Plots of the average percent of initial tumor volume (%) for each treatment group are shown. The following groups were examined: single dose of 64Cu-ATSM with 18.5, 37, 74, 111, or 148 MBq and saline injected on day 0 (n = 7/group), and multiple doses of 64Cu-ATSM with 37 MBq injected on days 0, 7, 21, and 28 (n = 7/group). Treatment schedule is also shown. Values are shown as the mean ± SD. (a, b) Different letters indicate significant differences (P < .05). (B) Tumor appearance in in vivo treatment study with 64Cu-ATSM. Representative tumor appearance is shown on day 0 (before administration), 26, 33, and 39 among the control group (upper) and a group treated with multiple doses of 64Cu-ATSM with 37 MBq × 4 (lower). Yellow arrows indicate the position of subcutaneously bearing tumors on the flanks of the mice. White dots surround the location of tumor presented on day 39. After four treatments with 64Cu-ATSM with 37 MBq, the tumor was not visible on day 39.